Trackway apparatus for train-control systems



2 Sheets-Shet- 1 W. K. HOWE ET AL a mwwfwmwm* B... D w? w? I QM W F 8m Original Filed'Jly 26. 1923 TRACKWAY APPARATUS FOR TRAIN 'CONTROL SYSTEMS Dec. 31, 1929.

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TRACKWAY APPARATUS FOR TRAIN CONTROL SYSTEIS 2 Sheets-Sheaif- 2 original Filed'uly 26, 1925 Patentecl Dec. 31, 1929 stars WINTHROP K. HOWE AND CHARLES S. BUSHNELL, OF ROCHESTER, NEW YORK, AS- SIGNORS T0 GENERAL RAILWAY SEGNAL COMPANY, OF ROCHESTER, NEW YORK 'IURACKVVAY APPARATUS FOR TRAIN-CONTROL SYSTEMS Original application filed July 26, 1923, Serial No. 653,898, nowrPatent No. 1,647,968, dated November 1, 1927.' Divided and this application filed September 17,19%. Serial No. 136,204.

rl`his invention relates to automatic train control systems of the so-called continuous inductive lcontrol type, and more particularly to the trackway apparatus and control circuits for such a system.

This application is a division of our prior application Ser; No. 653,898, filed July 26, 1923, now Patent No. 1,647,968, vdated November 1, 1927.' o

The primary object of the present invention is to'provide'traokway equipment and control circuits for train control systems of the continuous inductive type, which will permit the application of such' system to railroads having blocks of^diiferent lengths, so that the system will be adequate for safety and at the same time suitable for facilitating train moveinent. o

rifhe accompanying drawing illustrates on two sheets, designated Fig. 1A and Fig. 1B, intended to be arrangecl end to end, specific embodiments of the invention 'to' show its application tov different length blocks, together :with curves to facilitate explanation and unlderstading of the function and operation of this trackway apparatus and circuits.

rhe particular trackway equipment illustrated is intended for use with suitable carcarried speedV control' apparatus, such as shown in our prior application above mentioned. The significant characteristic of the car-carried speed control apparatus, to be used in connection with the trackway equipment of this invention, is that it is governed or responds to three different Vindications or controls, corresponding respectively to a high or maximum speed limit, to a medium or intermediate speed limit, and to a low or minimum speed limit. For convenience in eXplanation of the nature of the invention, it will be assumed hereinafter that this carcarried speed control apparatus is of the particular type shown in our prior application, in which two high and low speed cams are provided, and in which gradually reducing` or tapered speed limits are established Vby operation of the high cam from a high to a medium speed, and by the low cam from the medium speed to a low speed.

It requires a certain distance of travel,

or-dinarily termed braking distance, for a train toreduce its running speed by a brake application, either from a high to a medium' speed, 01' from a medium speed to a low speed. If it is desired to have the medium speed limit, for example, effective at a given point along the track, it is necessary that the apparatus enforcing the speed reduction from the high speed to this medium speed, specifically the high speed cam, should be 'efiective at a point in the rear of that given point at least as'great as braking distance for the train for a change from'such highito medium speeds. The same' is true for a change from the medium to the low speed limit. In other words there is a certain -distance of travel required to run 'out the high speed cam from' its initial high speed position to its low speed position, and a similar distance of travelis required to run down the low speed cam from its Vinitial medium speed position to' its ultimate low speed position. The ideal length of block for such a speed control system is one in which the high speed cam can be initiated at the entrance end of the block, and the low speed cam substantially vat the point where the high speed cam reaches its-runV down or medium speed position, said low speed cam reaching its ultimate low speed position at the exit end of the block.

In the practical application of speed control to i'ailroads, particularly to those railroads already equipped with a block signalsystem, it is found that the length of the blocks is di-fi'erent. The reasons'for such different lengths of blocks vary. For instance, the location of the block signals for visibility sometimes fiXes the location of the block ends in such a way that their length varies. Other practical Operating conditions, such as grades, low speed territory, and the like, require different length blocks.

These blocks encountered in practice may be either longer or shorter than the ideal block above mentioned. In case of a long block, if the high speed cam is started at the entrance end of that block, the train is required to reduce its speed sooner than necessary for safety.. On the other hand, for shortblocks,

the high speed cam must be started at some point in the rear of the entrance to that block, at least braking distance from its exit end, otherwise the reduction in speed is not started soon enough for safety. In the case of very short blocks, approximately as long as the run down distance of the low speed cam, this cam may used for the control throughout these short blocks. Situationsmay arise, however, where the desired block length will be somewhat longer than the run out distance of the low speed cam, but will be still less than the run out distance of both cams; and such a situation makes desirable a special arrangement of trackway circuits to provide the desired control at the proper point.

Referring to the accompanying drawing, it is assumed that the railway track will be divided by insulated joints into blocks in the usuail way. Three blocks, U, V and IV are shown, with the ends of adjac'ent blocks T and X. For convenience, corresponding Vparts associated With these different blocks are given the same reference characters with distinctive exponents. At the entrance to each block there is a signal Z, illustratedV as a semaphore signal. The control circuits for such block signals may be of any well known type, and have not been shown. These signals assume clear, caution, and stop positions in the usual way, familiar to those skilled in the art. Operated by each signal are circuit controllers, as 242 and 237, which are shown conventionally, and which open and close contacts in different p'ositions of the respective signal. The circuit controllers 242 and 237 close contacts from the clear or 90 position to the caution or 45 position, of the corresponding semaphore blade and other contacts in the stop or 0 position. The circuit contr'ollers '448 and 449 close different contacts in the 90 and 45 positions. These circuit controllers 448 and 449 associated with the signal Z3 for the block U are also closed between the 0o and 45 positions. The circuit controllers 452 close a contactfrom 900 to 45. The circuit controllers 466 and 467 Iof the signal Z5 close contacts in the 90, 45 and 0 positions, the 90 and 0 contacts being connected by a jumper. p I

Each block is supplied with an interrail alternating current potential from the secondary of a transformer 230, said secondary being connected to the track lrails 'by wires 233 and 234. The primary of this transformer 230 is connected to the secondary of a line transformer 235 through circuits Controlled by the circuit con'troliers :242 and 237 of the 'correspondingsignals so a`s to reverse 'the instantaneous polarity of 'this p otential when the signal changes from its clbarlor'caution 'position to itsstop position. `The line transfformer 235 is energized from the transmission line 244 connected 1to a generator 245. The 'interrail potential tlius provided causes Vcurrent to fiow down one track rail and back through the other in a circuit conveniently called the loop or track phase circuit.

In each block connected across the track rails at selected points are balancing resistances 450, 451, and so forth. Alternating current is supplied to the middle points of these resistances by circuits hereinafter explained, so that current flows from one resistance down both track rails in multiple to an adjacent resistance. This Circuit in which such current fiows is conventionally termed the Simplex or line phase circuit.

The currents in the track rails produced by these two loop and simplex circuits, suitably displaced in phase, are employed to cause operation of a three position car-carried relay (not shown), in a manner typical of the well known continuous inductive control type system, and familiar to those skilled in the art. This car-carried relay assumes one or the other of its energized positions, depending upon the relative instantaneous polarity of the currents in the loop and simplex circuits; and if either of these circuits is open, the relay assunies its de-energized position. Although it is the relative instantaneous polarities of the loop and Simplex cireuit currents which determine the operation of the carcarried relay, and in turn the speed limit effective, for simplicity and convenience these loop and Simplex circuits will be referred to as independently having a relative normal or reverse polarity. If these two loop and simplex c'ircuits bothV have a relative normal poarity, alclear or proceed indication Will be given, establishing the high speed limit and maintaini'ng inactive both the high and low 'speed cams. Likewise if both circuits are of arelative reverse polarity, the same is true. If either the loop or Simplex Circuit only is of the relative reverse polarity, the caution indication is transmitted, and the high speed cam is set into operation. If the Simplex cir- 'cuit current is cut off, the low speed cam is set into operation.

In the accompanying drawing, it has been attempted to illustrate certain assumed typical conditions of different block length, together with the particular control circuits required to provide the desired speed control for these different length blocks. Block U is representative of a block longer than the combined run out distance of the high and' 'low speed cams, or in other words, longer 'than 'the braking :distance for the normal speed running trains. The block V represents a block shorter than the run out distance of the two cams. a still shorter block.

, Above the track there has been shown on the drawing a series of permissive speed curves which represent the different speed liinits established by the high and 'low speed 'ca-ms. These curves are intended to corre- C1:

Block 7 represents spond approximately with the service braking distance of trains, so that by ordinary service brake appllcations, the running speed of the trains inay be inaintained below these speed limits, and also so that an automatic brake application initiated at any point on these curves will bring the train safely to a stop before reaching the end of the 'corresponding block. The letters A and B, with exponents corresponding to the blocks U, V and W, dicate the points along the track at which the high speed and low speed cams, respectively, should be set into operation.

Referring now to the block U, the trackway equipment of this invention is organized so that the change from a clear or proceed indication to a caution indication, which starts the high speed cain into operation, takes place at the point AU at an intermediate point in the block. To do this, special arrangements are made so that the polarity of the Simplex-circuit between the resistances 454 and 455 is reversed when the block U is a 'caution block and the signal Z3 assumes its caution position, this being necessary because, when the block U is a caution block and, the next block V in advance is occupied, the signal Z'JE is in the stop position, and the relative polarity of the loop Circuit 'current for the block TN is reversed by the circuit controllers 242 and 237 associated with the block V. The circuit connections by which this reversal of loop circuit current is obtained by operation of these circuit controllers can be readily traced on the drawing, an'd need not be specifically described. By reversing the relative polarity of the simplex circuit current between the resistances 454 and 455, when the 'block is a caution block, the car traveling in the first part of this block up to the point AU, picks up both loop and simplex circuit currents of relative reversed polarity, which of course produces the same efiect on the car-carried relay as if these currents were of the relative normal polarity. Accordingly, the middle points of the resistances 454 and 455 are connected to the circuit controllers 448 and 449 operated by the signal Z3, so that when this signal changes from its clear position to its caution or stop position, the relative polarity of these connections is reversed.

The simplex circuit current between the resistance 456 at the point AU and the resistance 457 at the point BU is supplied from the secondary of the transformer 2463, and has a fixed relative polarity. I

From the point BU to the end of the block, the Simplex circuit current should be cut oh, to start the low speed cam, when the block U is a caution block. Since the block U is assumed, as shown, to be followed by a short block V, requiring a reversal of relative polarity of the Simplex circuit current at the point AU, even though the block U is a clear block, at times when the block V is a 'caution block, it is necessary to divide the portion of' the trackway between point BU and the end of block U into two Sections, to provide the desired control, it being evident that this particular arrangement is not necessary if the block U were followed by a full length or a long block. Referring to the portion of track between the resistances 458 and 459, it can be seen that the simplex circuit current should be of the normal relative polarity when the block U is a clear block, that is, when the signal Z* is in the clear or caution position, rather than the stop position; and that this current should be cut off when the block U is a caution block, and the signal Z* is in the stop position. This control is provided by the operation of the circuit Controller 4524 of the signal Z4. Referring now to the remaining section of the block U between the resistances 460 and 461, the Simplex circuit current applied to this section should be of normal relative polarity when the block U is a clear block, of reverse relative polarity when the block V is a caution block, that is when signal Z*it indicates caution, and should be cut off when the block U is a caution block and the signal Z4 is in the stop position. This desired control'is provided by the 'circuit controllers 4484 and 4494 of the signal Z, contacts closed in the 90 and 45 positions of these circuit controllers being arranged to reverse relative polarity of the simplex circuit current.

Referring now to the blockV, the arrangement of control circuits to provide for starting the high speed cam into operation at the point AV in the block U when the block V is a caution block has already been pointed out. Between the entrance end of the block V and the point BV, where the low speed cam should be set into operation, the Simplex circuit current would normally be of fixed relation polarity, as in the case of the intermediate portion of the block U between the points AU and BU, except for the fact that, as shown, the block V is assumed to be followed by a very short block W which requires that the high speed cam be set into operation at the point AW in the block V. Consequently, itis necessary to sub-divide the portion of the block V from the entrance end to the point BV into two Sections, the portion between the resistances 462 and 463 being supplied with Simplex circuit current of fixed relative polarity from the transformer 2464, while the other portion, between the resistances 464 and 465, is supplied with Simplex circuit current having its relative polarity specially Controlled by the circuit controllers 466 and 467 operated by the signal Z7, so that the relative polarity ofV the simplex circuit current between these points is correct for the. different conditions. If the block l/V is a caution block, and the signal Z5 is in the caution position, even though the block Vis a clear block, the relative polarity of the Simplex circuit current between the resistances 464and 465 should be reversed, so as to cause operation of the high speed cam at the point AW. If the block VV is occupied, and the signal Z5 is in the stop position, then the block V is a, caution block, and the simplex Circuit vcurrent between the resistances 464 and 465 should be of thenormal relative polarity, since under these conditions the loop circuit current isreversed. Similarly, if both the blocks V and V are clear blocks, and the signal Z5 is in the clear position, then the simplex circuit current between the points 464 and 465 should be of the normal relative polarity. This desired, control is provided by the Circuit controllers 466 and 167, it being noted that these circuit controllers provide a normal relative polarity of simplex circuit current between the resistances 464 and 465 in the 90 and 0 positions of the signal ZS, end a rover-sed relative polarity in the position of this signal.

The portion of the block V from the point BV to the endmust also be subjected to control depending upon different conditions, in view of the. assumed arrangement of a short block 1W following the block V. If the block W is occupied, and the signal Z5 is in the stop positim, then the blOCk V S a caution block, and the Simplex Circuit current between the resistances 46.8 and 469 should be cut off, to start the low speed cam at the point BV, If the block W is a caution block, when the signal Zr is in the caution position, the Simplex circuit current between the resistances 468 and 469 should bc reVerSed in relative polarity, even though the block V is a clear block, in order to maintain the high speed cam, started at the point AW, in operation. If both the blocks W and V are clear, then the simplex circuit current between these two resistances should be of a relative normal polarity. This desired control is obtained by the circuit controllr 44:85- and 4495' operated bv the signal g Z. In the 90 position of the siugnal Z, the

Simplex circuit'current between the resistaHOBS 468 and 4:69 is of normai relative polrity, in the caution position of this signal, this Simplex Circuit current is oi' the reverse relativ polarity, and in the stop position of tis signal the Simplex ,circuit current is cut o Referring now to the block W, this block zllustrate/S the Condition of a short block, in which the high speed cam should be set into operation at a point AW in the block V in the rear, and also 4illustra-tes a case where the point BW, where ,the low speed cam should be started if the block W is a caution block, happens lto coiucide with the point AX, where the high speed cam should be started for proper control in asucceeding short block X, when said `short block X is a caution block. .The portion of the block VV between the resistcircuit current with fixed relative polarity from Jthe transformer 246. The portion of the block IV between the points BW and AX and the exit end of the block is utilized to opcrate the low speed cam when the block 7 is a caution block, and the high speed cam, when the next block X is a caution block. This portion of the block 7, therefore` requires a control the same as the portion of the block U between the resistances 460 and 461, and the same kind of Circuit controllers 4455 and 449" are employed.

If, as illustrated in our prior application above mentioned, the car-carried apparatus is arranged to requirc the engineer to make a special manipulation, termed acknowledgement, upon a change from clear to caution conditions, and from caution to stop conditions, it is desirablc to provide suitable markers along the trackway to indicate the points A and B at which such acknowledgment is to be taken. Triangular signs C are used to designate the point A, and a disc D is used to designate the point B.

From the typical cxamples illustrated in the drawings, and the principles hercinbefore explained, other adaptat-ions or modifications of the control circuits will be readily apparent which make it possible to apply a system of speed control to practically any particular length of block required. In this connection, it should be undcrstood that the conditions of safety require that thc speed limits shall be established at least braking distance from the point of required reduced speed and that conditions of facility of train operation make it expedient in some instances to delay establishing reduced speed limits and avoid train operation under reduced speeds unnecessary for safety. It should be understood that the particular scquence and arrangement of different blocks shown and described is merely rcpresentative or typical, and that various adaptations and modifications would bc made in practicing the principles of the invention. Also it should be understood that the particular type of track way control circuits shown, including the control by circuit controllers operated by the signals, is likewise merely illust-rative, and various modifications may be made without departing from the invcntion or the ideas of means underlying the same.

VVhat we claim is 1-- 1. In an automatic train control system of the continuous inductive type in which currents of different controlling characteristics may be supplied to the track rails of the dif- Vferent portions of track to aford clear 01' ing the supply of said currents to the track rails of said blocks to provide a clear indication throughout said block when the next block in advance is not occupied, said means acting When the next block in advance is occupied to provide a clear indication betwveen the entrance end of said block and an intermediate point therein at said braking distance from the exit end of the block and a caution indication for an intermediate portion of said block in advance of said intermediate point.

2. In an automatic train control system as specified in claim 1, the combination with a block longer than the braking distance for the normal running speed of trains, traffic Controlled means acting if the next block in advance of said long block is occupied to cut off' the supply of current to the track rails for a portion of said long block in the rear of its exit end.

3. In an automatic train control system as specified in claim 1, the combination With a block shorter than the braking distance for the normal running speed of trains immediatelyl following a block longer than said braking distance, of trackway means operable to provide, When the block next in advance of the short block is occupied, a clear indication in the long block from its entrance end to a point near its exit end at said braking distance from the exit end of the short block, and a caution indication throughout the remaining portion of said long block in advance of said point, said means also providing a caution indication for a portion of the short block at its entrance end When the block in advance thereof is occupied l. In a train control system as specified in claim 1, a combination With a block shorter than the braking distance for the normal running speed of trains immediately following a block longer than said braking distance, of traffic Controlled trackvvay means acting When the block next in advance of the short block is occ-upied to cut off the supply of the current to the track rails of the short block for a portion of its length in the rear of its exit end. l

In testimony Whereof we hereby aflix our signatures.

WINTHROP K. HOWE. CHARLES S. BUSHNELL. 

